The store's fifth floor is completely transformed until Jan. 2, filled with chocolate Alexander McQueen armadillo shoes, studded press-on nails, and candle replicas of Gaga’s head that cry when lit. Inflatable cartoonish sculptures and taxicab wraps promoted the opening around the city, and Barneys's windows, too, have been Gaga-fied. "My favorite window I think is [the] one window that looks like my boudoir and it's covered in blonde hair," Gaga told WWD. "It's gorgeous."

Despite all the expenditure, Barneys expects to break even on the promotion, its chief executive Mark Lee said. Twenty-five percent of the workshop's sales will go to Gaga's new Born This Way Foundation, which focuses on youth empowerment; Lee added that the store hopes to raise over $1 million for the cause.

A behind-the-scenes video, below, and images of the windows, workshop, and launch party guests in the slideshow.